What is meldonium?

Meldonium (also known as Mildronate) is used to treat
inadequate blood flow to the organs, especially the heart.

According to the Latvian pharmaceutical company Grindex, which manufactures the
drug, it helps protect patients with chest pain caused by heart
disease against tissue
damage, chronic heart failure, and brain circulation
disorders.

It can also improve physical capacity and mental function —
in everyone, not just those with disorders.

Sharapova said she'd been taking the drug since 2006 because of
several
health concerns, including magnesium deficiency, irregular
results on a heart function test called an EKG, and
diabetes, which she said runs in her family.

What does it do to the body?

In people with diabestes, taking meldonium along
with other drugs may help lesson symptoms and severity
of the illness, according to some
animal studies and severeral small studies of
the drug in people.

Who's taking it?

Clive Brunskill/Getty Images

Sharapova said she was unaware the drug had been added to the
list of banned substances.

"For the past 10 years I have been taking a medicine called
Mildronate by my doctor, my family doctor, and a few days ago
after I received the letter from the ITF [International Tennis
Federation] I found out it also has another name of meldonium,
which I did not know," Sharapova said, according to the
BBC.

She added that she had been legally taking the medicine for the
past decade.

Still, Sharapova isn't the only athlete who's tested
positive for meldonium. Former European ice-dancing champion
Ekaterina Bobrova told Russian media in March that she'd
failed a test for the drug as well, the
AP reported. And in February, some news
agencies reported
that former world champion 1,500-meter runner Abeba Aregawi had
tested positive for the drug.